Interrupter structure for circuit breaker with individual blast valves and timedelayed upstream cutoff valve

ABSTRACT

A plurality of series-connected interrupters are connected in series and are mounted in a low-pressure tank. Pairs of the interrupters are mounted on a high-pressure tank filled with SF6 gas. Each individual interrupter contains its own blast valve, adjacent cooperating contacts and disposed radially interiorly of a main cooperating contact section, and radially exteriorly of an arcing contact section. Each of the individual interrupters further contain an upstream cutoff valve which cuts off the flow of high-pressure gas after an interruption operation. A time delay is provided for the operation of the cutoff valves.

United States Patent n91 McConnell et al.

[ INTERRUPTER STRUCTURE FOR CIRCUIT BREAKER WITH INDIVIDUAL BLAST VALVES AND TIME-DELAYED UPSTRE CUTOFF VALVE [75] inventors: Lorne D. McConnell, Radnor;

Hansruedi Aumayer, Newtown Square, both of Pa.

[73] Assignee: I-T-E Imperial Corporation,

Philadelphia, Pa.

[22] Filed: Aug. 27,1971 [21]. Appl. No.: 175,507

[52] US Cl. 200/148 B, 200/148 BV [51] Int. Cl. H0lh 33/80 [58] Field of Search 200/ 148 B [56] References Cited UNlTED STATES PATENTS 3,612,799 10/197] Carter ZOO/148B cm] 3,823,289 [451 July 9, 1974 3,670,126- 6/1972 Roidt ZOO/I48 B Primary Examiner-R0bert S. Macon Attorney, Agent, or Firm-Ostrolenk, Faber, Gerb & Soffen [5 7 ABSTRACT A plurality of series-connected interrupters are connected in series and are mounted in a low-pressure tank. Pairs of the interrupters are mounted on a highpressure tank filled with SP gas. Each individual interrupter contains its own blast valve, adjacent cooperating contacts and disposed radially interiorly of a main cooperating contact section, and radially exteriorly of an arcing contact section. Each of the individual interrupters further contain an upstream cutoff valve which cuts off the flow of high-pressure gas after an interruptionoperation. A time delay is provided for the operation of the cutoff valves.

8 Claims, 4 Drawing Figures BACKGROUND OF THE INVENTION This invention relates to gas blast circuit breakers, and more specifically relates to a novel interrupter structure for use in gas blast circuit breakers.

This invention is an improvement of the interrupter structure shown in US. Pat. No. 3,495,057, in the name of Golota, issued Feb. I0, 1970, and assigned to the assignee of the present invention. In that patent, there is shown a gas blast circuit breaker in which a plurality of interrupter structures, each containing a pair of coooperating contacts, are connected in series within a low-pressure housing. High-pressure containers mounted within the low-pressure tank then support respective pairs of interrupters, with a single blast valve allowing gas to be released from the high-pressure tank to the two interrupters when the contacts are opened. Anauxiliary sliding sleeve on the main blast valve allows a time delay for beginning the blast during contact closing.

The interrupter shown in the above-noted patent was designed to interrupt currents up to 43,000 amperes. However, the interrupter must be modified to interrupt currents of 63,000 amperes. Moreover, the mechanical structure used in the interrupter of the above patent is expensive to manufacture and is difficult to adjust.

BRIEF SUMMARY OF THE INVENTION In accordance with the present invention, the coop- I erating contacts and separate blast valve arrangement for each interrupter are made to use the general concepts of the interrupter shown in copending application Ser. No. 823,115, filed May 8, 1969, in the name of Jensen, now US. Pat. 3,614,357, issued Oct. 19, 1971 and assigned to the assign-ee of the present invention. Thus, each interrupter is provided with its own blast valve which is placed immediately adjacent the separating contacts (and radially'between the main contacts and arcing contacts). Therefore, blast gas is available at the instant the contacts open, thereby to increase the interrupting capacity of the interrupter.

The novel structure of the invention permits the elim- .ination of movable baffles and allows flexible mounting of the stationary contact to the interrupter housing. Moreover, a finger contact arrangement is used for the stationary contact (rather than a continuous orifice). The blast valve and gas-conducting passageways are arranged to provide a two-way blast through the are drawn by the separating contacts, thereby to increase interrupting ability.

Each of the interrupters are then provided with a time-delay cutoff valve, disposed upstream of the blast valve and contacts. The cutoff valve is arranged to close to prevent gas flow some predetermined time after the opening of the blast valve. The cutoff valve will then stay closed until or just before the contacts and blast valve are reclosed, to prevent excessive flow of gas during closing.

A single spider plate is provided at the bottom of the interrupter and contains spaced passages, connected by webs, which passages lead from the high-pressure-tank to the interior of the interrupter and a region upstream of the blast valve. A further passage in at least one of the webs of the spider plate then communicates from a region downstream of the blast valve to the interior of the low-pressure tank.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I schematically illustrates acircuit breaker which uses four series-connected interrupters constructed in accordance with the invention.

FIG. 2 is a sectional view of one of the interrupters of FIG. I with the contacts closed.

FIG. 3 is a sectional view similar to that of FIG. 2 with the contacts open.

FIG. 4 is a perspective view of the rear of the spider plate of FIGS. 2'and 3.

DETAILED DESCRIPTION OF THE DRAWINGS Referring first to FIG. ll, there is schematically illustrated a circuit breaker of the type which can use the interrupters of the invention. Thus, the circuit breaker includes a suitably supported conductive low-pressure housing 10, which receives conventional gas connections and operating mechanism linkages. Some of this detail is shown in the above-noted US. Pat. No. 3,495,057, and is unimportant to an understanding of the present invention.

Two insulation pedestals II and 112 are mounted within tank 110 and on a platform 13 which is mounted within tank 10. Suitable operating mechanisms are provided which apply longitudinal movement to operating rods 14 and 15, disposed within insulators Ill and 12, respectively, and which apply operating movement to the movable parts of the interrupters to be described.

Conductive high-pressure tanks 16 and 17 are mounted on top of insulators ill and I2 and may be filled with high-pressure SP or other suitable gas through the hollow insulators lland 12, respectively. l-landholes, such as covered openings 16a and 17a, may be provided to allow access to the interior of tanks 16 and 117, respectively. I

Tanks I6 and 117 then each support two interrupters 18-19 and 20-211, respectively. Each of the interrupters, to bedescribed in detail in FIGS. 2, 3 and 4, contain a single breaking gap and are connected in series. The four series interrupters I8 to 21, shown in FIG. I, are used to form one pole of a 230 Kv circuit breaker. Additional interrupters can be used in series to form higher voltage ratings. Thus, six interrupters would be used to reach a rating of 345 Kv. It will be noted, as shown in dotted lines 22 and 23, that a suitable linkage within tanks 16 and 17, respectively, is coupled to interrupters llS-ll9 and 20-211, respectively, to operate these interrupters between open and closed conditions responsive to operation of rods 14 and 15, respectively.

The tops of interrupters l8 and 21, and the stationary contacts therein, are connected to the interior ends of the conductive studs 30 and 31 of terminal bushings 32 and 33, respectively. Bushings 32 and 33 enter tank 10' in a sealed manner and may themselves be filled with SF,;, and are surrounded by shields 34 and 35, respectively, within the tank 110. The bottoms of interrupters in a live tank configuration. The tops of the interrupters 19 and 20, and the stationary contacts therein, may be directly joined as shown in FIG. 1, thereby to complete the series connection of interrupters 18 to 21.

The structure of one of the interrupters 18 to 21, for example, interrupter 18, is shown in detail in FIGS. 2 and 3. Referring now to FIGS. 2 and 3, the interrupter 18 is supported within a hollow elongated insulation tube 50 which may be of fiber glass, and which contains shoulders 51 and 52 at its opposite ends. Shoulder 50 is then adapted to receive conductive member 53, which is suitably secured to stationary contact support member 54. The stationary contact support member 54 is, in turn, connected as by a flexible shunt 55, shown in FIG. I, to the bottom conductive stud 56 of bushing 32. Note that a suitable corona shield 57, also shown in FIG. 1, may enclose the top of the interrupter 18 (with similar shields providedfor interrupters 19 to 21) and the bottom of bushing 32.

The lower end of insulation tube 50 receives a bolt ring 60 (FIGS. 1 to 3) which is suitably bolted to casting portion61 of high-pressure housing 16. Note that similar casting portions 62, 63 and 64 are provided on the high-pressure tanks 16 and 17 of FIG. 1 to serve to support the other interrupters 19, 20 and 21. It will be further seen that the movable contacts of inerrupters 18 and 19 and of the interrupters 20 and 21 may be electrically connected through the conductive material of tanks 16 and 17 which might be made of aluminum. Alternatively, suitable conductive shunts may be used in-parallel with tanks 16 and 17, so that these tanks need not carry electrical current of a substantial magnitude, as compared to the rated current to be carried by the circuit breaker.

The bottom of casting 61 then presses against a stationary spider-type plate 70, which is best shown in FIGS. 2, 3 and 4 as containing a central tubular member 71, and outer peripheral section 72, and three web sections, best shown in FIG. 4 as web sections 73, 74 and 75. The openings defined between web sections 73, 74 and 75 communicate with the interior of tank 16 through the conductive casting 61. A channel 76 is further formed in the web section 75, which channel is aligned with an opening 77 in bolt ring 60, thereby to define a channel which communicates with the interior of the relatively low-pressure main tank 10.

As will be seen hereinafter, blast gas will exit through the aligned channels 76 and 77, as well as through the central opening 80 in conductive member 54 at the other end of the interrupter. It will be further noted that the opening 80, as shown in FIG. 1, will also communicate with the low-pressure interior. of tank through suitable openings in the shield 57.

The central opening defined by member 71 of plate 70 is closed off by sealing plates 81 and 82, which are suitably clamped across the opening in member 71, and have appropriate sealing rings to slidingly receive an operating rod 90 which axially slides within the openings in plates 81 and 82. Suitable sliding seals are provided to prevent leakage of high-pressure gas of from within casting 61 into the internal region of section 71 of spider plate 70.

As shown in FIG. 1, the operating rod 90 is suitably connected to the operating linkage 22, which causes operation of the interrupter. The spider plate 70 further receives the valve seat of an upstream cutoff valve, wherein the sealing ring 91 is contained between clamping plates 92 and 93. Since the sealing ring 91 is disposed upstream of the movable contacts, which will be described hereinafter, it will be seen that its sealing surface will not be exposed to are products during the operation of the interrupter. Note that suitable sealing rings are provided where needed to provide a good pressure seal for members 91, 92 and 93.

The internal section 71 of plate then further receives a conductive ring in sealed relation therewith and the ring 100, in turn, carries a first main sliding contact ring 101, which will be seen more fully hereinafter to receive a movable contact in sliding relation therewith, with a clamping plate 102 holding the main sliding contact 102 in position. The sliding contact 101 may be of any desired type and could, for example, consist of radially disposed fingers pressed inwardly toward the axis of the interrupter. The outer surface of ring 100 further serves as a sliding support and guide for the movable valve sleeve 110, which serves as the movable member of the upstream cutoff valve. FIG. 2 shows this valve in its open position, while FIG. 3 shows the valve closed. A shoulder 111 in sliding sleeve serves as a stop to limit the possible movement of sleeve 110 toward the upper end of the interrupter.

Turning next to the stationary contact construction, it will be seen that stationary contact fingers, such as the fingers and 121 of FIGS. 2 and 3, are disposed in a circular cluster around the end of the internal flange 121 of conductive member 54. Note that the internal opening 80 is defined by the interior surface of flange 122. The upper end of the contact fingers, such as contact fingers 120 and 121 (typically there can be twelve contact fingers in a circular cluster) are pivoted at their upper ends against the end of flange 122 and are solidly electrically connected to the conductive member 54, through flexible shunts, shown for fingers 120 and 121 as shunts 123 and 124, respectively. The stationary contact fingers 120 and 121 will be seen more fully hereinafter to form the stationary arcing contact structure and contains arcing contact material inserts 125 and 126, respectively.

The conductive ring 53 further carries an outer ring 127 (which is suitably sealed to member 53), where the outer ring 127 carries suitable biasing springs for each of the stationary arcing contact fingers, shown as biasing springs 128 and 129 for contact fingers 120 and 121. Note that the springs, suchas springs 128 and 129, can be seated in insulation pads to prevent a current path through the spring material which could limit the spring life. Conductive cylinder 127 further serves as a support for the main stationary contact ring 130 which is clamped to member 127 by the clamping ring 131. The stationary contact ring 130 may be similar in construction to main stationary contact 101, with inwardly directed contact pressures being suitably provided.

There is also provided between member 127- and clamping ring 131 a further blast valve ring 132 which contains an axially directed protrusion 133, which will be seen hereinafter to define the blast valve stationary ring member for the blast valve of the interrupter. It should be noted that this blast valve ring is disposed between the arcing contacts, such as arcing contact inserts 125 and 126 for the stationary contact and the main contacts 130 for the stationary contact.

The movable contact structure may now be described as shown in FIGS. 2 and 3 as consisting of a main movable cylindrical member 14% which is connected to the operating shaft 911 by a conductive spider member 141, which is threadably connected to the lower end of the movable contact member 1411, and to the upper end of operating rod W. Note that spider member 141 has an arcing tip 141a.

An interior channel 142, through the movable contact body 1411, is thus permitted to communicate with the annular channel 143 between member 71 of spider plate 70 and operating rod 911. This channel 143 then communicates with channels 76 and 77 in the spider plate 711 and bolt ring 611, and then to the lowpressure region within tank 111.

The movable contact body 1411 is terminated with an arcing contact ring 144, which can make, as shown in FIG. 2, high-pressure contact to the arcing contact fingers, such as fingers 1211'and 121 contact.

A main movable contact surface is then defined by the outer surface 145 which slidably engages the interior of the main stationary contact ring 1311. Note that contact surface 145 is so designed that the arcing contacts will engage before the main contacts engage of the stationary (so thatthe arcing contacts take all closing duty) andfurther that the main contacts separate before the arcing contacts separate (so that all interrupting duty is absorbed by the arcing contacts).

The movable contact member 14% is further designed to receive the main blast valve seat 1511, which cooperates with the blast valve ring member 133 to form a blast valve seal when the contacts are in the closed positionof F IG. 2. Member 1411 further serves as a means to carry a suitable support ring 16d, which has an interior shoulder 1151 at its bottom end which receives the top shoulder 162 of upstream cutoff valve member 1111. Thus, the ring member 1611, which may be a split ring to permit suitable assembly, moves with the movable contact assembly and causes operation of the upstream cutoff valve in a manner to be described hereinafter.

The operation of the interrupter is as follows With the breaker in the closed condition, as shown in FIG. 2, a current path is defined from the conductive member 54, through the flexible shunts, such as shunts 123 and 1124, into the contact fingers 1120 and 121. In parallel with this conductive path is the main conductive path, which will have a relatively low resistance and includes conductive members 53 and 127 to the main stationary contact 1311. Current then goes from the main stationary contact 1311 into the contact surface 145 of movable contact member 1411. In parallel with this, there is some current transfer through the higher resistance path including the movable arcing contact tip 144 and into movable contact member 1411. Current then transfers into the second fixed contact 1111 and into conductive ring 11111 to the spider plate 711 and casting 151. u I

In the closed position, it will also be observed that the blast valve members 133 and 1511 are sealed and that highpressure gas from the interior of tank 16 fills the region within interrupter tube 511 up to the blast valve seal. Note that the upstream cutoff valve member 11111 is in its open position when the contacts are closed. Thus, the main movable contacts including contact members 133 and 145 are immersed in high-pressure gas, such as sulfur 'hexafluoride, while the arcing contacts including the arcing contact 144 are immediately adjacent high-pressure gas which is held outside separation of the main contacts 1311 and 135 and opening of the blast valves 133 and 1511 before the arcing contacts, including arcing contact 144, and fingers 1211 and 121 separate. Thus, current is transferred from the main contact surfaces without arcing and a copious flow fo high-pressure sulfur hexaflouride begins to flow through the arcing contacts. Accordingly, at the instant the arcing contacts separate, they are subjected to this strong flow of interrupting gas. It should be noted that gas flow will take the two directions through the arc shown in F161, 3 by-the arrows 1711 and-171 so that there will be improved arc interruption. The gas blast will also transfer the are from insert 144 to arcing tip 141a of the movable contact 1411.

Generally, the orifice sizes which conduct sulfur hexaflouride gas are such that there will be approximately equal flow in the directions 1711 and 171. The gas passing in the direction of arrow 1711 will exit directly from the top of the interrupter while the gas moving in the direction of arrow 171 moves through channel 143 and out through the bottom of the interrupter. Preferably, the gas vented during arc interruption is vented in a direction generally perpendicular to the plane containing interrupters 13 to 211 to avoid the possible coating of the outer surfaces of the insulation tubes, such as insulation tube 511, of the interrupters with are contamination products.

As the movable contact member 1411 continues to move downwardly toward its fully open position shown in FIG. 3, the interior shoulder 15b of the split ring 1611 picks up the upper end 151 of sleeve 1111 and moves the sleeve 1111 toward its valve closed position, shown in FIG. 3.

The intentional time delay caused by the distance between shoulder 1311 and end section'151, when the contacts are closed (as in FIG.2), causes an intentional time delay in the closing of the upstream cutoff valve to insure that gas blast action can proceed for a sufficiently long time to insure proper arc interruption. Once this time has passed and the movable contact has reached its fully open position, however, the construction insures the closing of the upstream cutoff valve, as in FIG. 3. The contacts and valves will now sit in this position until it is desired to close the circuit breaker.

only a small blast of gas in necessary prior to closing to handle arc prestriking as the contacts close. if desired, the full travel in the lost motion connection between members 1110 and 1111 may be sufficiently long during closing so that there is no'blast of gas during the closing of the contacts.

In the arrangement shown in the drawings, however, and just before the contacts close, the upstream valve members 110 and 91 are opened, so that there is a short blast of gas while the arcing contact 144 engages the arcing contact fingers, such as fingers 120 and 121. After these fingers have been engaged, the main contacts 130 and 145 close, with substantially no arcing duty in view of the prior closure of the arcing contacts and the blast valve 133-150 is closed to shut off the flow of gas from the high-pressure tank and hold this high-pressure gas in the region immediately adjacent the area of contact interruption for the next opening operation.

Although this invention has been described with respect to preferred embodiments, it should be understood that many variations and modifications will now be obvious to those skilled in the art and, therefore, the scope of this invention is to be limited, not by the specific disclosure herein, but only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. An interrupter for a gas blast circuit breaker; said interrupter comprising, in combination:

a stationary contact having a gas channel therethrough; one end of said channel permanently communicating with a relatively low-pressure ambient region;

a movable contact longitudinally movable along an axis of said interrupter between an engaged and disengaged position;

a blast valve comprising a stationary valve ring means secured to said stationary contact and surrounding said gas channel therein, and a movable valve ring means secured to said movable contact; said stationary and movable valve ring means being coaxial with the said axis of said interrupter and being movable into and out of sealing engagement with respect to one another when said movable contact moves into and out of engagement with respect to said stationary contact;

conduit means extending through said movable contact and terminating at one end interiorly 'of said movable valve ring means, and permanently terminating at another end in said relatively lowpressure ambient region;

high-pressure conduit means communicating with the exterior of said stationary and movable valve ring means, whereby high pressure may be applied to the interior of said interrupter and adjacent the region of engagement of said movable and stationary contacts but is isolated from said gas channel in said movable and stationary contacts when said movable and stationary valve ring means are in their said position of sealing engagement;

upstream cutoff valve means disposed in said highpressure conduit means and comprising a movable valve member mounted on said movable contact and a stationary valve member; said movable valve member being moved into valve sealing engagement with said stationary valve member when said movable contact moves to its said disengaged position relative to said stationary contact;

and lost motion connection means for mechanically connecting said movable valve member to said movable contact.

2. The interrupter of claim 1 wherein said stationary contact comprises a plurality of individual contact fingers disposed in a generally circular cluster and radial biasing means for radially biasing said plurality of contact fingers into contact with said movable contact.

3. The interrupter of claim ll wherein said stationary contact comprises a plurality of circularly disposed arcing contact fingers and a circularly disposed main contact member concentrically surrounding said arcing contact fingers of said stationary contact; said movable contact comprising a circularly disposed arcing contact engageable with saidstationary arcing contact fingers and a circularly disposed main movable contact member engageable with said main contact member of said stationary contact.

4. The interrupter of claim 3 wherein said stationary and movable valve ring means of said blast valve are disposed radially between said arcing contacts and said main contact members of said movableand stationary contacts, respectively.

5. The interrupter of claim 1 wherein said upstream cutoff valve means comprises a cylinder slidably mounted on the outer surface of said movable contact.

6. The interrupter of claim 1 which further includes an insulation support tube for receiving internally therein said movable and stationary contacts, said blast valve and said upstream cutoff valve means, and for defining at least a portion of said high-pressure conduit means.

7. The interrupter of claim 6 wherein said movable and stationary contacts are mechanically secured to said insulation support tube. v

8. The interrupter of claim 6 which further includes support means for slidably supporting said movable contact; said support means including an elongated conductive tube which slidably receives said movable contact and a' spider plate for mounting said conductive tube; said spider plate being secured to said insulation support tube and containing a plurality of openings joined by web sections; said plurality of openings communicatingwith said high-pressure conduit means; at least one of said web sections having an opening therethrough; said opening in said web section communicating with said low-pressure ambient region. 

1. An interrupter for a gas blast circuit breaker; said interrupter comprising, in combination: a stationary contact having a gas channel therethrough; one end of said channel permanently communicating with a relatively low-pressure ambient region; a movable contact longitudinally movable along an axis of said interrupter between an engaged and disengaged position; a blast valve comprising a stationary valve ring means secured to said stationary contact and surrounding said gas channel therein, and a movable valve ring means secured to said movable contact; said stationary and movable valve ring means being coaxial with the said axis of said interrupter and being movable into and out of sealing engagement with respect to one another when said movable contact moves into and out of engagement with respect to said stationary contact; conduit means extending through said movable contact and terminating at one end interiorly of said movable valve ring means, and permanently terminating at another end in said relatively low-pressure ambient region; high-pressure conduit means communicating with the exterior of said stationary and movable valve ring means, whereby high pressure may be applied to the interiOr of said interrupter and adjacent the region of engagement of said movable and stationary contacts but is isolated from said gas channel in said movable and stationary contacts when said movable and stationary valve ring means are in their said position of sealing engagement; upstream cutoff valve means disposed in said high-pressure conduit means and comprising a movable valve member mounted on said movable contact and a stationary valve member; said movable valve member being moved into valve sealing engagement with said stationary valve member when said movable contact moves to its said disengaged position relative to said stationary contact; and lost motion connection means for mechanically connecting said movable valve member to said movable contact.
 2. The interrupter of claim 1 wherein said stationary contact comprises a plurality of individual contact fingers disposed in a generally circular cluster and radial biasing means for radially biasing said plurality of contact fingers into contact with said movable contact.
 3. The interrupter of claim 1 wherein said stationary contact comprises a plurality of circularly disposed arcing contact fingers and a circularly disposed main contact member concentrically surrounding said arcing contact fingers of said stationary contact; said movable contact comprising a circularly disposed arcing contact engageable with said stationary arcing contact fingers and a circularly disposed main movable contact member engageable with said main contact member of said stationary contact.
 4. The interrupter of claim 3 wherein said stationary and movable valve ring means of said blast valve are disposed radially between said arcing contacts and said main contact members of said movable and stationary contacts, respectively.
 5. The interrupter of claim 1 wherein said upstream cutoff valve means comprises a cylinder slidably mounted on the outer surface of said movable contact.
 6. The interrupter of claim 1 which further includes an insulation support tube for receiving internally therein said movable and stationary contacts, said blast valve and said upstream cutoff valve means, and for defining at least a portion of said high-pressure conduit means.
 7. The interrupter of claim 6 wherein said movable and stationary contacts are mechanically secured to said insulation support tube.
 8. The interrupter of claim 6 which further includes support means for slidably supporting said movable contact; said support means including an elongated conductive tube which slidably receives said movable contact and a spider plate for mounting said conductive tube; said spider plate being secured to said insulation support tube and containing a plurality of openings joined by web sections; said plurality of openings communicating with said high-pressure conduit means; at least one of said web sections having an opening therethrough; said opening in said web section communicating with said low-pressure ambient region. 